Where are you guy finding different sizes water pump pullies? I tried the usually places, Mancini, 440 source, summit, and found only the “stock” size.
If you have a factory service manual you can see the pulley sizes they used.
The idiotic aftermarket is so in love with the notion that slowing the water pump down to save 5 HP that they ignore the power they piss away from the cooling system not functioning.
